Celica L4-122 1998cc 2.0L DOHC Turbo (3S-GTE) (1990)
Variable Boost Control Solenoid: Description and Operation
Turbocharger Pressure Vacuum Switching Valve Circuit Schematic
The Turbocharger Pressure Vacuum Switching Valve (VSV), located on the RH side of the engine, allows the EFI Electronic Control Unit (ECU) to
control Wastegate Actuator operation. Instead of spring tension only relieving actuator pressure and closing the Wastegate Valve, the ECU grounds the
Turbocharger Pressure VSV and allows pressure to escape back to the intake tube, pre-turbo inlet. This system provides for faster Wastegate operation
and allows for ECU control based on input from the Knock Control Sensor. For testing and diagnosis of the ECU and Knock Control Sensor, refer to
COMPUTERIZED ENGINE CONTROLS. The Turbocharger Pressure VSV inputs the ECU through terminal TPC.